Cloning Of Na~+/H~+ Antiporter Gene From Total DNA Of Enriched Culture Of Sedimentary Soil Samples From Daban Salt Lake In Xinjiang

Halophiles can survive in the condition with high salt, due to their special cellular structure and metabolic mechanism in recent years widespread attention by the scientific community. In this study, two Na+/H+ antiporter genes designated nhadl and nhar was cloned from total DNA of partially digested with Sau3AI of enriched culture of sedimentary soil samples from Daban Salt Lake in Xinjiang by functional complementation and expressed in the antiporter-deficient Escherichia coli strain KNabc. The deduced amino acid sequence of NhaDl consists of 426 residues with a calculated molecular mass of 45,826Da. which was 63% identical to arsenical pump family protein of C. sticklandii DSM 519.The hydropathy profile was characteristic of a membrane protein with 11 putative transmembrane domains. The deduced amino acid sequence of NhaR consists of 392 residues with a calculated molecular mass of 41981.2 Da, which was 65% identical to sodium/hydrogen exchanger of A. metalliredigens QYMF. The hydropathy profile was characteristic of a membrane protein with 10 putative transmembrane domains.The effects of NaCl concentrations and pH7.0-9.0 conditions on the growth of E. coli KNabc cells carrying nhadl and nhar were tested, respectively. The results show that nhadl and nhar gene confer the ability upon E. coli KNabc cells to grow under NaCl and alkaline pH conditions.